import sys
import pygame
from settings import Settings
from ship import Ship
from bullet import Bullet
from time import sleep
from alien import Alien
from game_stats import GameStats


class AlienInvasion:
    """管理游戏资源和行为的类"""

    def __init__(self):
        """初始化游戏并创建游戏资源"""
        pygame.init()

        self.settings = Settings()

        self.screen = pygame.display.set_mode((0,0),pygame.FULLSCREEN)
        self.settings.screen_width = self.screen.get_rect().width
        self.settings.screen_height = self.screen.get_rect().height

        # self.screen = pygame.display.set_mode((self.settings.screen_width, self.settings.screen_height))

        pygame.display.set_caption("Alien Invasion")

        self.stats = GameStats(self)
        self.ship = Ship(self)
        self.bullets = pygame.sprite.Group()
        self.aliens = pygame.sprite.Group()

        self._create_fleet()

    # 设置背景颜色
    # self.bg_color = (230,230,230)

    def run_game(self):
        """开始游戏的主循环"""
        while True:
            # 监视键盘和鼠标事件
            self._check_events()
            if self.stats.game_active:
                self.ship.update()
                self._update_bullet()
                self._update_alien()
            self._update_screen()
            


    def _check_events(self):
        """响应按键和鼠标事件"""
        for event in pygame.event.get():
            #control quit
            if event.type == pygame.QUIT:
                sys.exit()
            #control move right
            elif event.type == pygame.KEYDOWN:
               self._check_keydown_events(event)
            elif event.type == pygame.KEYUP:
                self._check_keyup_events(event)


    def _check_keydown_events(self, event):
        """ response keydown"""
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = True
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = True
        elif event.key == pygame.K_q:
            sys.exit()
        elif event.key == pygame.K_SPACE:
            self._fire_bullet()


    def _check_keyup_events(self, event):
        """ response keyup"""
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = False
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = False

    def _fire_bullet(self):
        """create new bullet"""
        if len(self.bullets) < self.settings.bullets_allowed:
            new_bullet = Bullet(self)
            self.bullets.add(new_bullet)

    def _update_bullet(self):
        self.bullets.update()
        for bullet in self.bullets.copy():
            if bullet.rect.bottom <= 0:
                self.bullets.remove(bullet)
        self._check_bullet_alien_collisions()


    def _check_bullet_alien_collisions(self):
        collisions = pygame.sprite.groupcollide(self.bullets, self.aliens, True, True)
        if not self.aliens:
            self.bullets.empty()
            self._create_fleet()





    def _update_screen(self):
        """更新屏幕图像，并切换到新屏幕"""
        self.screen.fill(self.settings.bg_color)
        self.ship.blitme()
        for bullet in self.bullets.sprites():
            bullet.draw_bullet()
        self.aliens.draw(self.screen)
        # 让最近绘制的屏幕可见
        pygame.display.flip()

    def _create_fleet(self):
        """create alien"""
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        available_space_x = self.settings.screen_width - (2 * alien_width)
        number_aliens_x = available_space_x // (2 * alien_width)

        ship_height = self.ship.rect.height
        availiable_space_y = (self.settings.screen_height - (3 * alien_height) - ship_height)

        number_rows = availiable_space_y // (2 * alien_height)

        for row_number in range(number_rows):
            for alien_number in range(number_aliens_x):
                self._create_alien(alien_number, row_number)




    def _create_alien(self, alien_number, row_number):
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        alien.x = alien_width + 2 * alien_width * alien_number
        alien.rect.x = alien.x
        alien.rect.y = alien.rect.height + 2 * alien.rect.height * row_number
        self.aliens.add(alien)

    def _update_alien(self):
        self._check_fleet_edges()
        self.aliens.update()

        if pygame.sprite.spritecollideany(self.ship, self.aliens):
            self._ship_hit()

        self._check_aliens_bottom()

    def _check_fleet_edges(self):
        for alien in self.aliens.sprites():
            if alien.check_edges():
                self._change_fleet_direction()
                break

    def _change_fleet_direction(self):
        for alien in self.aliens.sprites():
            alien.rect.y += self.settings.fleet_drop_speed
        self.settings.fleet_direction *= -1

    def _ship_hit(self):
        if self.stats.ships_left > 0:
            self.stats.ships_left -= 1

            self.aliens.empty()
            self.bullets.empty()

            self._create_fleet()
            self.ship.center_ship()

            sleep(0.5)
        else:
            self.stats.game_active = False

    def _check_aliens_bottom(self):
        screen_rect = self.screen.get_rect()
        for alien in self.aliens.sprites():
            if alien.rect.bottom >= screen_rect.bottom:
                self._ship_hit()
                break


if __name__ == '__main__':
    # 创建游戏实例并运行游戏
    ai = AlienInvasion()
    ai.run_game()
